Field of the Invention
The present invention relates to wireless communication, and more particularly, to a periodic channel state information (CSI) reporting method performed by a terminal in a wireless communication system and a terminal using the method.
Related Art
The International Telecommunication Union Radio Communication Sector (ITU-R) is conducting a standardization operation of International Mobile Telecommunication (IMT)-Advanced which is a next-generation mobile communication system after 3rd generation. The IMT-Advanced aims to support IP (Internet Protocol) based multimedia service at data rate of 1 Gbps in stationary and low-speed moving states and 100 Mbps in a high-speed moving state.
The 3rd Generation Partnership Project (3GPP) as a system standard that meets the requirements of the IMT-Advanced prepares for LTE-Advanced (LTE-A) created by improving Long Term Evolution (LTE) based on Orthogonal Frequency Division Multiple Access (OFDMA)/Single Carrier-Frequency Division Multiple Access (SC-FDMA). The LTE-A is one of the strong candidates for the IMT-Advanced.
An LTE-A system adopts carrier aggregation (CA) and in this case, the carrier aggregation means aggregating multiple component carriers (CCs) and receiving and transmitting the aggregated component carriers (CCs). The component carriers may be divided into a primary component carrier (PCC) and a secondary component carrier (SCC). The primary component carrier (PCC) may be referred to as a primary cell (Pcell). In addition, other component carriers other than one primary component carrier (PCC) may be defined as the secondary component carrier (SCC), the secondary component carrier may be referred to as a secondary cell (SCell), and a UE may perform uplink transmission through the secondary cell.
As described above, a plurality of secondary cells may be configured for one primary cell. In this case, when a large number of cells are configured in one primary cell (i.e., a cell having a reference value (predetermined value) or more is configured in one primary cell), since information on a large number of secondary cells needs to be by using only a PUCCH and/or PUSCH of one primary cell, there may be a problem in that a payload of information on the secondary cell transmitted to a base station is excessively increased.
For example, assuming that 32 primary cells are configured in one primary cell, a terminal may need to transmit information of 32 secondary cells using only the PUCCH of the primary cell, and as a result, the payload of the information on the secondary cell transmitted in the primary cell may be excessively increased.
Accordingly, the present invention intends to provide a method for efficiently transmitting information related to a plurality of cells to the base station when a large number of cells are configured as a carrier aggregation technique.